Randomized Controlled Clinical Trial of CAD/CAM and Conventionally Fabricated Singl Implant Abutments.
|First Received Date ICMJE||October 27, 2010|
|Last Updated Date||October 27, 2010|
|Start Date ICMJE||May 2009|
|Primary Completion Date||Not Provided|
|Current Primary Outcome Measures ICMJE
||The aim of this randomized controlled clinical trial is to examine single-tooth implant abutments and restorations in the esthetic zone.|
|Original Primary Outcome Measures ICMJE||Same as current|
|Change History||No Changes Posted|
|Current Secondary Outcome Measures ICMJE
||Test group will achieve better biologic and esthetic outcomes when compared to control group|
|Original Secondary Outcome Measures ICMJE||Same as current|
|Current Other Outcome Measures ICMJE||Not Provided|
|Original Other Outcome Measures ICMJE||Not Provided|
|Brief Title ICMJE||Randomized Controlled Clinical Trial of CAD/CAM and Conventionally Fabricated Singl Implant Abutments.|
|Official Title ICMJE||A Comparison of Zirconia CAD/CAM and Conventionally Fabricated Single Implant Abutments and Restorations in the Esthetic Zone: a Randomized Controlled Clinical Trial.|
CAD/CAM technology has been introduced to the field of implant dentistry in the beginning of 1990's (Priest 2005). Since their introduction, the use of CAD/CAM technology in the production of dental implant restorations has been rapidly expanding. However, little evidence is currently present supporting its clinical viability (Henriksson 2003, Canullo 2007).
Therefore, the suggested prospective randomized study includes bone level placed Straumann implants restored with transmucosal elements and crowns fabricated using either CAD/CAM "Etkon" technology (Zirconia abutment and ceramic crown) or a conventional technique (Crossfit titanium abutment and a ceramometal crown).
The aim of this randomized controlled clinical trial is to examine single-tooth implant restorations in the esthetic zone. An esthetic area is defined as any area that is visible in the patient's full smile. [3rd ITI consensus conference 2004] The rehabilitations will be fabricated using two different techniques. Zirconia CAD/CAM (ZCC) implant restorations (tests) will be compared to Titanium conventionally-fabricated (TCF) implant restorations (controls) using, reproducible esthetic (objective/subjective) and biologic parameters.
This in vivo study is a randomized study with two groups of 15 patients with one implant each for a total of 30 patients and 30 implants. The implants will be examined for successful tissue integration according to the criteria of success (Buser et al. 1990) at every recall visit.
In addition, the following parameters will be evaluated for each restoration:
Finally, an evaluation of the mechanical, biologic and technical complications will be performed at every recall visit. Mechanical complications would be defined as those complications that involve the prosthesis such as abutment screw loosening, fracture of the veneer material, fracture of the crown framework, abutment screw fractures, and implant fractures. The category of biologic complications will include those complications that involve the soft tissues (e.g., fistula, suppuration, bleeding, gingival inflammation, and soft tissue dehiscence). Technical complications are defined as those related to restorative components and crowns (e.g. crown emergence profile, abutment and crown fit, screw loosening, ceramic fracture).
Long-term prospective studies demonstrate a high success rate of Straumann implants in partially or fully edentulous patients both with early and conventional loading (Salvi et al. 2004, Lambrecht et al. 2003, Cochran et al. 2002, Weber et al. 2000, Buser et al. 1997). Before the introduction of CAD/CAM technology to the field of implant dentistry in the beginning of 1990's (Priest 2005), the available approach for restoring single dental implants was either with stock or cast custom abutments and a ceramo-metal crowns. In spite of the satisfactory results that this conventional treatment approach has achieved, several disadvantages have been recognized. First, non tooth-colored abutments possess the problem of bluish appearance of overlying tissue in cases of thin gingival biotype (Barclay et al. 1996, Prestipino and Ingber, 1996). Second, with stock abutments ideal emergence profile can not be achieved (Daftary 1997), a disadvantage that was reduced with the use of custom abutments. However, custom abutments present other disadvantages including possible imprecision of fit due to inaccuracies associated with impression, waxing, investing and casting procedures and the negative effect of the gold alloy on the peri-implant mucosal barrier as demonstrated by Abrahamsson in 1998 (Abrahamsson et al 1998 ).
The introduction of CAD/CAM technology to implant dentistry was meant to provide higher quality restorations. Since its introduction, the use of this technology in the production of implant ceramic frameworks and crowns especially in esthetic regions has been rapidly expanding because of the promising esthetic, biologic, and mechanical properties. Alumina as well as Zirconia abutments are characterized by good tissue compatibility (Abrahamsson et al. 1998). In a study by Barclay et al in 1996 it was found that plaque accumulation scores for ceramic-coated transmucosal elements were significantly lower than those recorded in titanium transmucosal elements (Barclay et al. 1996). These results suggest that the further development of a ceramic implant transmucosal collar may assist plaque control at the soft tissue-implant interface and may favorably influence the tissues in this region (Barclay et al. 1996). Other studies documented no significant differences in plaque accumulation and microbial colonization between titanium and ceramic abutment samples (Andersson et al. 2003, Rasperini et al. 1998). The bacterial colonization of Zirconia ceramic surfaces was recently studied in vitro and in vivo (Rimondini et al. 2002). The authors found that, overall, Zirconia ceramic surfaces developed for implant abutments accumulate fewer bacteria than commercially pure titanium, and may therefore be considered as a promising material for abutment manufacturing (Rimondini et al. 2002). A comparison of the recorded superficial soft tissue responses to titanium and ceramic surfaces of transmucosal elements of implants revealed no significant differences between both groups (Barclay et al. 1996, Andersson et al. 2001). Almost no marginal bone loss was recorded, indicating a stable bone situation both at ceramic and titatium abutments on single-tooth implants (Andersson et al. 2001). However, it seems to be that the peri-implant soft tissues adjacent to titanium and ceramic surfaces may differ in features that are not apparent when routine clinical parameters are used (Barclay et al. 1996).
Because of their specific mechanical properties, all-ceramic restorations demonstrate a lower fracture resistance than ceramic restorations supported by metal substructures. The ceramic abutments on implants are more sensitive to fracture and to handling procedures than the titanium abutments (Andersson et al. 2001). However, advances have been made in the fabrication of high-strength all-ceramic abutments for anterior implants (Yildirim et al. 2003). The hardness of the Zirconium ceramic also allows it to undergo conventional prophylaxis with ultrasonic scalers without alteration of its surface quality of abutment (Marzouk, 1996). Moreover, Zirconia has a flexural strength and fracture toughness almost twice as high as alumina (Glauser et al. 2004, Yildirim et al. 2003).
Currently very limited number of clinical studies is present supporting the clinical viability of CAD/CAM ceramic restorations (Henriksson 2003, Canullo 2007) and no reports were found on the performance of CAD/CAM ceramic implant restorations in comparison to conventional implant restorations.
The aim of this randomized controlled clinical trial is to examine single-tooth implant abutments and restorations in the esthetic zone. Restorations will be fabricated using two different techniques. Zirconia CAD/CAM (ZCC) implant abutments and restorations will be compared to conventional, prefabricated Titanium (TCF) implant abutments and porcelain-fused-to-metal restorations using reproducible aesthetic (objective/subjective) and biologic parameters.
The hypothesis of this investigation is that ZCC implant abutments/restorations (test group) will achieve better biologic and esthetic outcomes when compared with TCF types (control group). The null hypothesis is defined as follows: ZCC implant abutments/restorations and TCF implant restorations are indistinguishable when biologic and esthetic outcomes are compared.
CAD/CAM technology has been involved in the fabrication of dental abutments and restoration for the purpose of improving the biologic and esthetic results. This assumption has been formulated primarily from subjective interpretations as objective assessments from randomized controlled trials are sparse at best. This study will be significant for clinical dentistry in that it will create evidence on the clinical long-term performance of Zirconium CAD/CAM abutments and ceramic crowns compared to stock titanium abutments and porcelain-fused-to-metal restorations using subjective and objective evaluation parameters that will be statistically compared.
Materials and Methods:
Patients with an indication for an implant supported single tooth restoration in the esthetic zone will be included in the study according to the following criteria:
Subject population Patients will be recruited from the patient pool of the Teaching and Faculty Practice at the Harvard School of Dental Medicine. A 12-month period will be allowed to enroll the patients in this study. The mean treatment outcome will be compared between the two randomized patient groups, allowing for detection of the smallest clinically important differences between these means (TheSealedEnvelope™- http://www.thesealedenvelope.com/ power.php).
Patient entry (informed consent, patient registration, randomization and blinding) An informed consent approved by the Harvard Medical School/Harvard School of Dental Medicine Committee on Human Studies will be obtained for all subjects to be entered in this study. Its conduct will adhere to the principles outlined by the Office for Research Subject Protection of the Harvard Medical School / Harvard School of Dental Medicine. Each subject will be randomly assigned to one of the two treatment options. A random permuted block approach will be used to allocate patients into one of the treatment groups. A sealed envelope containing the treatment group (control or test group) will be assigned to each patient. Subsequently and according to the assigned treatment, a ZCC restoration (test group) or a TCF ceramo-metal (control group) will be fabricated and delivered to the clinician.
For subjective evaluation the trial design will be on a double blinding level, which means that neither patients nor expert clinicians will know which treatment the patients are randomized to. This can be achieved by concealing allocation information from patients and by using expert clinicians, who are otherwise not involved in the patients' care, to assess treatment difficulties and outcomes without knowing their treatment group.
30 patients will be randomly allocated to control or test group presented in Table (1)
Group (n= 30 patients) Implant Abutment Crown Loading Test group (n=15) ZCC BL Straumann Etkon Zirconia Cement-retained Etkon Zirconia 6-8 weeks control group (n=15) TCF BL Straumann Crossfit titanium Cement-retained PFM 6-8 weeks
Evaluation Parameters and time schedule:
Patients will be evaluated for esthetic (objective and subjective parameters) and biologic parameters as well as the success criteria through out the study period. The baseline measurements are defined as the measurements taken during the healing period after insertion of bone level implant.
During the healing period, after insertion of a Straumann Bone Level implant following standard surgical procedures, patients will use removable provisional prostheses.
The implants will be examined for successful tissue integration according to the criteria of success (Buser et al. 1990) at every recall.
Criteria of success:
Esthetic parameters :
Parameters Follow-up time schedule Baseline At insertion 1 month 6 months 1 year 3 years 5 years
Parameters Follow-up Time schedule Baseline Crown Insertion 1 mos 6 mos 1 year 3 years 5 years
D. Mechanical, Biologic and Technical complications An evaluation of the mechanical, biologic and technical complications will be performed at every recall visit. Mechanical complications would be defined as all those complications that involve the prosthesis such as abutment screw loosening, fracture of the veneer material, fracture of the crown framework, abutment screw fractures, and implant fractures. The category of biologic complications will include the complications that involve the soft tissues ex. fistulas, suppuration, bleeding, gingival inflammation, and soft tissue dehiscence. Technical complications would be defined as those complications that are related to lab procedures and fabricating techniques ex. abutment and crown emergence profile, abutment and crown fit.
Complications Follow-up Time Schedule Baseline At insertion 1 mo 6 mos 1 year 3 years 5 years
Statistical Analysis: After data collection and completion of the investigation, a one-way analysis of variance (ANOVA) will be used to compare the mean values of all objective and subjective parameters. Their variance will be broken down into two components: (a) "between groups" component (control group vs. test group) at baseline, crown insertion, and each follow-up period and (b) "within group" component at baseline, crown insertion, and each follow-up period. A multiple LSD range test (confidence level 95%) will be applied to determine which means differ statistically from each other.
Timetable June 2009 beginning of the study May 2010 deadline for patients' entry and allocation August 2010 deadline for data collection of baseline and crown insertion measurements September 2010 deadline for data collection of 1-month follow up measurements February 2011 deadline for data collection of 6-month follow up measurements August 2011 deadline for data collection of 12-month follow up measurements August 2012 deadline for data collection of 24-month follow up measurements August 2013 deadline for data collection of 36-month follow up measurements August 2014 deadline for data collection of 48th month follow up measurements August 2015 deadline for data collection of 60th month follow up measurements February 2016 deadline for final publication of data
Belser UC, Gruetter L, Vailati F, Bornstein MM, Weber HP, Buser D. Outcome evaluation of early placed maxillary anterior single-tooth Implants using objective esthetic criteria:
a cross-sectional retrospective study in 45 patients with a 2- to 4-year follow-up using pink and white esthetic scores. J Periodontol 2009; 80: 140-151.
|Study Type ICMJE||Interventional|
|Study Phase||Not Provided|
|Study Design ICMJE||Allocation: Randomized|
|Intervention ICMJE||Device: dental implants - zirconia abutmetns - prefabricated abutments|
|Study Arms||Active Comparator: Prefabricated Abutment
Intervention: Device: dental implants - zirconia abutmetns - prefabricated abutments
|Publications *||Not Provided|
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
|Recruitment Status ICMJE||Active, not recruiting|
|Completion Date||Not Provided|
|Primary Completion Date||Not Provided|
|Eligibility Criteria ICMJE||
1. Adjacent implant 2. Presence of periapical radiolucencies at the adjacent teeth 3. Missing adjacent teeth 4. Local inflammation, including untreated periodontitis. 5. Persistent intraoral infections. 6. Untreated mucosal diseases.
|Ages||21 Years and older (Adult, Senior)|
|Accepts Healthy Volunteers||Yes|
|Contacts ICMJE||Contact information is only displayed when the study is recruiting subjects|
|Listed Location Countries ICMJE||Not Provided|
|Removed Location Countries|
|NCT Number ICMJE||NCT01229995|
|Other Study ID Numbers ICMJE||M17719-104|
|Has Data Monitoring Committee||Yes|
|U.S. FDA-regulated Product||Not Provided|
|Plan to Share Data||Not Provided|
|IPD Description||Not Provided|
|Responsible Party||German O. Gallucci, Harvard School of Dental Medicine|
|Study Sponsor ICMJE||Harvard School of Dental Medicine|
|Collaborators ICMJE||Not Provided|
|Information Provided By||Harvard School of Dental Medicine|
|Verification Date||October 2010|
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